The rotating wheel, as a transfer device that synchronously meshes with with one moving conveyor and transfers objects to another conveyor, has been used extensively, because it provides positions or "stations" for accomplishing operations on the objects, while allowing the operating mechanisms to remain stationary to the objects while they are still on the transfer wheel.
Both mechanical grasping devices and vacuum operated suction cups have been used to pick up and release the containers on rotating transfer wheels. Both of these general methods must be accomplished with synchronism of movement at the point where the stations on the perephery of the tranfer wheel mesh with stations on both the delivery and pick up conveyor systems. When designing similar systems to operate at higher transfer rates, all of the timing, grasping, releasing, and tolerance problems are greatly amplified. This is particularly true when using the more gentle and less abrasive vacuum cup grasping method.
It is, therefore, one major object of this invention to provide a sensor activated impulse means to move accurately define the synchronizing of the pick up and release points for a very high rate transfer wheel; when utilizing the vacuum grasping method for rotating containers.
When using suction cups for grasping the containers at the stated radial mesh points, the vacuum cups must go through a deformation or compliance to the curved surface of the container that is to be picked up; which requires relatively fine adjustment of all the radial assemblies on the wheel; by (1) adjusting the radius of all the radial mounted pick ups, or (2) moving the whole wheel assembly toward or away from the mesh points with the first and second horizontal conveyors; which can be interactive if both parallel conveyors are fixed.
It is, therefore, another object of this invention to provide a simple "automatic" means to momentarily adjust to a wider range of accumulative tolerances in the size of the containers, the individual radial pick up arms, and the retaining structure on the conveyor belts; to enable higher pick up and release rates.
The compliance or deforming of typical suction cups, when radially meshing with a curved container surface to obtain a vacuum seal, can require relatively large movements of air to help draw the non conforming lips of the vacuum cups to the curved surface. Large movement of controlled air become a limitation to faster timing; for pick up and release of the containers at the higher operating rates.
It is, therefore, still another object of this invention to provide a means of adding a sensor activated means for momentarily applying an impulse of controlled pressure on the vacuum cups, at the meshing point of the vacuum cups with the face of the containers, to force a quick but gentle full contact and vacuum seal; which enables lower volumes of vacuum and air pressure to be quickly controlled during the pick up and release of containers at the higher transfer rates.
When containers are not of uniform width from top to bottom (having a tapered front panel) the problems of acquiring a full contact and seal of the vacuum cup pickups is further magnified; and especially at higher transfer rates.
It is, therefore, yet another object of this invention to provide, with a momentary compensating feature of the vacuum pick up, a means to automatically adjust to containers with a tapered front panel; as well as a range of widths.
In the general field of container unscramablers and handlers, it is a highly desirable feature to design the machinery to have a minimum amount of parts to change, when switching from one sized container to another; since the multiple parts; the labor; and the downtime; are all expensive to the end user.
It was a additional objective in utilizing vacuum pick-up of the containers, to incorporate simple coaxial elements for rotating the container while on the transfer wheel. The parts are economical to produce; have a minimum of weight and inertia at the higher rates and, consequently, are adaptable to being directly driven by electronically programmed stepping motors for any rotation angle. The above elements, including a momentary air driven contact feature, combine to cover a wide range of adaptations, without change-over parts or multiple fine adjustments on the rotary orientation wheel.